Tracer rounds have been included in multiple firing guns almost as a standard. Because of the significant aid that tracer rounds provide in adjusting the path of projectile travel toward the intended target, tracer rounds are included in almost every rapid fire armament ammunition.
The function of the tracer round is to produce a representation of the path of the projectile that is visible to the operator of the gun in order to allow the operator to adjust the path and reach the target. Depending upon the frequency of firing, the percentage of tracer rounds in the total number of rounds will vary, from a very high percentage when very short bursts are fired or if firing is `semiautomatic` rather than fully automatic, to a somewhat lower percentage when firing long bursts of large numbers of rounds. In any case it is necessary for the operator or an observer reporting to the operator to see the tracer round.
One example of a conventional tracer round is shown in U.S. Pat. No. 3,633,512, to Schlack et al. In this design, a tracer mix is incorporated into the tracer cavity of a self destructive projectile such that there is a forward high explosive cavity and a rearward tracer cavity. The round has become typical of conventional usage of tracer designs since its development in the 1970's.
In prior art designs, when increased visibility of the tracer round was desired, it was usually accomplished simply by increasing the diameter of the tracer column to provide a larger cross sectional area. This adjustment provides a larger viewing surface and hence greater visibility.
Modern projectiles have evolved, however, in ways that do not permit the old methods to resolve visibility problems. For example, the 25 mm M919 round is a high velocity, maximum range round that is being developed for various applications such as the Bradley Fighting Vehicle and other uses. It is a 25 mm round that is approximately the size of the pencil. Because of its range and speed, the tracer round is difficult to see.
Another technical advance that has caused difficulty for tracer rounds is the use of laser hardened optics and thermal viewers. As lasers are being considered for aiming devices and even for defensive measures, it has become important to shield the eyes of the observer from laser radiation. Techniques are available to accomplish that goal but in so protecting the eyes of the observer, visibility particularly of tracer rounds for fast and long range projectiles has decreased. In the case of the M919, for example, the tracer round cannot be seen through the most preferred laser hardened optics and the thermal viewer.
Prior art methods described above for increasing the cross sectional area were not available due to the configuration of the round, mainly in the diameter and other dimensions. For that reason, it is an object of this invention to provide a way to increase the visibility of tracer rounds through laser hardened optics and thermal viewers.
Another object is to provide an improved pyrotechnic mixture that can be used in tracer rounds to increase visibility of the tracer round while avoiding mechanical alteration or design changes.
Other objects will appear hereinafter.